Human-induced changes in animal populations and distributions, and the subsequent effects on fluvial systems

Crayfish and fish as bioturbators of streambed sediments: Assessing joint effects of species with different mechanistic abilities

“…The knowledge about physical factors complicating this scenario is steadily increasing (e.g., Billi et al, 1992;Wilcock, 1998;Pyrce and Ashmore, 2003;MacKinnon et al, 2004;Pearce and Walker, 2005), and mobile animals complicate this scenario even more: they have diverse mechanistic abilities to modify solid surfaces and to increase or decrease the transport of solids, and these animal actions vary in space and time (e.g., Butler, 1995;Statzner et al, 2003b;Butler, 2006). Thus, for a start, quantifications of such action of animals focused on separate singlespecies assessments of mammals (e.g., Butler, 1995;Trimble and Mendel, 1995;Butler, 2006), salmonids and other fish groups (e.g., Flecker, 1996;Montgomery et al, 1996;DeVries, 1997;Rennie and Millar, 2000;Gottesfeld et al, 2004), and many groups of marine invertebrates (e.g., Fager, 1964;Eckman et al, 1981;Meadows et al, 1990;Willows et al, 1998;François et al, 1999;Botto and Iribarne, 2000;Katrak and Bird, 2003;Jackson et al, 2005; see also the review by Murray et al, 2002) or freshwater invertebrates (e.g., McCall and Tevesz, 1982;Statzner et al, 1996;Parkyn et al, 1997;Statzner et al, 1999;2000;MermillodBlondin et al, 2002;Creed and Reed, 2004;Usio and Townsend, 2004;Takao et al, 2006).…”

Importance of Burrow-Entrance Mounds of Gunnison's Prairie Dogs (Cynomys gunnisoni) for Vigilance and Mixing of Soil

“…Mounds usually are neither disproportionately downhill on slopes (Longhurst, 1944) nor do they have specific orientation on flat areas (Bailey, 1931;Scheffer, 1947). For burrowing mammals, size (i.e., surface area and volume) of mound varies (Vogel et al, 1973) and whether the mound at the opening to burrows correlates with size of burrow system is questionable (Butler, 2006;Schulz, 1978). Each burrow system of C. ludovicianus mixes ca.…”

“…200-225 kg of soil (Whicker and Detling, 1988). With 50-300 openings and 25-300 systems/ha (Butler, 2006) this translates to 5,000-67,500 kg of mixing of soil/ha. The extent of mixing of soil by prairie dogs is considerable in terms of processes in soil and modification of habitat (Hansell, 1993).…”

“…We estimated density of mounds and number of prairie dogs by dividing the count of inhabited burrows by three because we assumed that on average three openings belong to one burrow system (Butler, 2006;Verdolin et al, 2008). We estimated size of population by multiplying number of prairie dogs in our 10,000-m 2 observation areas by area of the entire colony.…”

“…Information on volume of burrows can be applied to situations where prairie dogs are being translocated and established in artificial burrows. 4) During construction of burrow systems, Gunnison's prairie dogs move and mix 10,000-16,500 kg of soil/ha, which is within the range excavated by black-tailed prairie dogs (Butler, 2006).…”